A familiar safety item used by countless handball and racquetball players is next to useless for preventing serious injury, according to safety researchers at several universities.

Lensless eyeguards allow a speeding handball, racquetball or squash ball- traveling at up to 140 miles an hour-to squeeze inside their open frames, causing many serious eye injuries each year.

Alex Cooper of Huntington Woods, Mich., was recently hurt while wearing such a guard. Now he wants to warn others.

``You`ll find the vast majority of players on courts have inadequate eye protection, and the No. 1 problem is lensless eye guards,`` Cooper says. Other players wear no guards at all or wear ordinary prescription glasses.

Risky sports

Court sports-including racquetball, tennis, squash, handball, paddleball, badminton and volleyball-are the leading cause of sports eye injuries to Americans 25 and older, according to the National Society to Prevent Blindness, based in Schaumburg. In November, the society renewed a media campaign to warn about eye injuries in such sports, zeroing in on lensless eyeguards.

Cooper, 33, has been playing handball for nearly two decades. He was struck by a handball Nov. 8.

``My opponent hit a line drive right into my eye, probably one of the hardest shots of our day. That ball came right inside the eye guard (and)

skidded my contact lens right across my eye,`` Cooper says. He suffered a torn retina, which was repaired with laser surgery.

He still has limited night vision and won`t know the permanent extent of his injury for months. ``I can`t tell you how disgusted I am, because I thought I had eye protection. The worst part is, there are people out there like me who think they are protected,`` says Cooper, a healthcare consultant. Failing the tests

Turriff says sports officials and equipment makers have wrestled for years with the need to establish eyeguard standards. Until they do, consumers must pick and choose. Ordinary plastics aren`t tough enough, nor are regular prescription glasses, even industrial-duty styles.

Major sports associations have differing views as well:

- Racquetball: Last December, the American Amateur Racquetball Association began requiring ``lensed eyewear designed for racquet sports`` in the 1,200-plus U.S. tournaments it sanctions each year.

``We recommend polycarbonate lenses, 3 millimeters thick, but that`s a standard we`ve had to leave up to the manufacturers,`` says Michael Arnolt, who pushed for the requirement as the association`s rules commissioner last year.

``Wearing open eyeguards is almost like wearing no eyeguards,`` he adds.

``A racquetball will penetrate the (opening) at about 50 m.p.h., and the average player hits the ball about 70 m.p.h.``

- Squash: Same rule as for racquetball. ``We suggest eye protection for everyday play, but we can`t enforce it,`` says Robert Kingsley, associate director of the U.S. Squash Racquets Association.